Combine heads with conveyor belts have been described in GB 1 501 639 A, GB 1 574 033 A, and GB 1 602 067 A. These heads have a frame with a base, side walls, and a rear wall. A transverse conveyor spiral is arranged in front of the rear wall. Several conveyor belts arranged in a laterally sequential manner are located above the base, and between a mower bar at the front side of the base and the transverse conveyor spiral, and rotate around front and rear rollers and transport the material to be harvested and that has been cut off by the mower bar, rearward toward the transverse conveyor spiral which then delivers it in its middle region to the oblique conveyor of a harvester combine. A rotating reel is located above the mower bar and the conveyor belts and feeds the material to be harvested and that is standing upright to the mower bar. Smaller gaps remain between the belts' lateral edges adjacent to one another and are covered over at the top by roof-shaped metal covers.
A different head, with conveyor belts that rearwardly transport the material to be harvested, is described in EP 1 495 665 A, where plate-shaped covers cover over the lateral edges of the conveyor belts and the intermediate zones that remain between adjacent conveyor belts. The covers are intended to prevent the material to be harvested, or other contaminants, from penetrating the inner zone of the conveyor belt assemblies.
At the rear side of the conveyor belts in the case of the combine heads that are being described, the transverse conveyor spiral transports the material to be harvested transversely with respect to the forward direction and toward the middle of the combine head. In the case of larger throughput quantities of the material to be harvested, said material is pushed from the rear to the rear sides of the conveyor belts, and this can lead to the undesired consequence that certain quantities of material find their way between the conveyor belt located upstream relative to the material conveyance direction of the transverse conveyor spiral and the cover and thence through into the inner zone of the conveyor belts and there cause damage.
A conveyor belt is described in DE 299 10 397 U for the conveyance of bulk materials and materials comprising individual units. In order to prevent the situation in which bulk material residues find their way into the inner zone of the conveyor belt and adversely affect the conveyor belt or its securement elements and drive elements there, it is proposed that the lateral ends of the conveyor belt have a projection or a thickened region that projects outward from the surface of the conveyor belt. The problem in the case of which the material to be transported is transported transversely with respect to the conveyance direction does not present itself here, however, so that the person skilled in the art is not induced to use such a projection on a combine head of the type designated at the beginning.